Penner had been a columnist and covered the Olympics, the Angels, World Cup soccer, tennis and sports media for The Times. In 2007, he announced that he was a transsexual.

A file photo of Mike Penner, and at right, Christine Daniels. (Los Angeles Times )

Mike Penner, a longtime Los Angeles Times sportswriter who made headlines in 2007 when he announced that he was transsexual, has died. He was 52.

Penner was pronounced dead Friday evening at Brotman Medical Center in Culver City, a Los Angeles County coroner's official said.

The cause of death has not been determined but was believed to be suicide.

"Mike was a first-rate journalist, a valued member of our staff for 25 years, and we will miss him," Times Editor Russ Stanton said. "He respected our readers a great deal, enough to share with them his very personal journey. Our thoughts and prayers are with his family."

A versatile member of The Times' sports staff, Penner covered the Olympics, the Angels, World Cup soccer, tennis, sports media and a variety of other assignments.

He also spent several years writing a sports column for the paper's Orange County Edition. Since 2008, he was the principal writer for the sports section's "Totally Random" feature.

"Mike was one of the most talented writers I've ever worked with, capable of reporting on any number of topics with great wit and style," sports editor Mike James said. "This is a tragic ending and a difficult time for all of us who knew him."

In a 2001 season preview for the then-struggling Dodgers, Penner wrote:

"The sins of the father on one coast have been revisited by the son on the other. Welcome to Flatbush West. Brooklyn had the wrecking ball crashing down on Ebbets Field, Los Angeles had Peter O'Malley selling out to Fox."

And in 1986 when the Angels lost in the playoffs to the Boston Red Sox, he wrote about the team running into "Angel karma. . . . In the end, it was all a big tease, the biggest yet . . . the karma remained untied and unbeaten."

Penner was born Oct. 10, 1957, in Inglewood and graduated from Western High School in Anaheim and Cal State Fullerton. He joined The Times' Orange County Edition in 1983 as a staff writer, covering high school sports.

He had previously worked at the Anaheim Bulletin as a writer and sports editor.

In April 2007, Penner surprised colleagues and readers with an essay in The Times' Sports section announcing that he was "a transsexual sportswriter."

"It has taken more than 40 years, a million tears and hundreds of hours of soul-searching therapy for me to work up the courage to type those words," he wrote.

Times Associate Editor Randy Harvey, who was the paper's sports editor at the time, said the essay allowed Penner to explain in his own way a decision that "we realized would be a human-interest story and a news story. We didn't want it to be filtered through someone else's lens."

In the essay, Penner said of his transgender decision:

"I gave it as good a fight as I possibly could. I went more than 40 hard rounds with it. Eventually, though, you realize you are only fighting yourself and your happiness and your mental health -- a no-win situation any way you look at it."

Writing as Christine Daniels, Penner started a column for the paper's website in May 2007 called Day in L.A. and a blog about the transition, then in July began writing for the paper again.

He returned to using the Mike Penner byline in October 2008.

Penner is survived by his brother, John, a copy editor at The Times, and his former wife, Times staff writer Lisa Dillman.